Thin film composite (TFC) membranes are frequently used in forward osmosis, reverse osmosis (RO), and nanofiltration systems for the purification of tap water, seawater and brackish water, ultra-pure water production, wastewater treatments, and separation of organics from aqueous streams. A variety of TFC membranes exist, including those developed from polymeric materials such as polyurea, polyamide, polyether, polyurea-amide, and aromatic polyamides. Commonly used TFC membranes are those made with a porous, highly permeable support such as polysulfone, which is coated with a cross-linked aromatic polyamide thin film. Performance of such membranes in terms of permeability, selectivity and antifouling performance predominantly depends on the properties of the membrane, particularly the thin film, or discriminating, layer.
Thus, there remains a need to develop TFC membranes, including reverse osmosis, forward osmosis, and nanofiltration membranes, that achieve high flux and exhibit maintained or improved rejection characteristics when used in the purification of water. Also desired are methods for making the membranes. Accordingly, it is among the objects herein to provide TFC membranes that achieve high flux and retain or exhibit improved rejection characteristics, and methods for making the membranes.